Pipe splitting apparatus with replaceable blade

ABSTRACT

Pipe splitting apparatuses and systems including a replaceable blade, and methods therefor, are provided. In various examples, a pipe splitting apparatus includes an outer surface including a recess. A blade including a portion is disposed within the recess. A hardenable material is disposed within the recess. The hardenable material is configured to flow upon application to fill empty space within the recess and at least partially around the portion of the blade disposed within the recess. The hardenable material is further configured to harden after application to secure the portion of the blade within the recess and fix the blade to the pipe splitting apparatus.

RELATED APPLICATIONS

This patent application claims the benefit of priority, to U.S. patentapplication Ser. No. 12/895,304, filed on Sep. 30, 2010 and issued onDec. 11, 2012 as U.S. Pat. No. 8,328,468, and which claims the benefitof priority to U.S. Provisional Patent Application Ser. No. 61/248,713,filed on Oct. 5, 2009, which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

This patent document pertains generally to pipe splitting and moreparticularly, but not by way of limitation, to a pipe splittingapparatus with a replaceable blade.

BACKGROUND

Pipe, such as plastic, copper, lead pipe, and the like, has been usedfor connecting homes to and creating networks for utilities, forinstance, water, sewage, and natural gas. As pipes become older, theybreak down, crack, develop scaling on interior surfaces that can clogthe pipe, and the like and thereby require replacement.

A technique known as pipe bursting is currently used as a convenientmethod to replace underground pipe without the need to completelyexcavate the pipe needing replacement. A pipe breaking device, such asan expander or a mole, is pulled by a cable through the existing pipewhile it is still underground. The expander is designed to break, splitor burst the pipe, and at the same time push the old pipe into thesurrounding soil. The expansion of the old pipe allows the expander topull a replacement pipe into place.

In one example, pipe splitters include one or more blades extending froman outer surface of a pipe splitter section. The one or more blades canbe used to split or aid in splitting the pipe. Over time, the one ormore blades can become worn and less effective at splitting or aiding insplitting the pipe. Over enough time and use, the one or more blades canbecome so worn and ineffective as to require replacement, at which pointthe entire pipe splitter section would have to be replaced. Such pipesplitter sections can be relatively difficult and/or relativelyexpensive to machine or otherwise manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 is a perspective view of an example of a pipe splitter includinga blade portion with replaceable blades;

FIG. 2 is a top plan view of the pipe splitter of FIG. 1;

FIG. 3 is a side elevational view of the pipe splitter of FIG. 1;

FIG. 4 is a cross-sectional view of the pipe splitter of FIG. 1, thecross section taken along line 4-4 in FIG. 3;

FIG. 5 is a front elevational view of the pipe splitter of FIG. 1;

FIG. 6 is a perspective view of an example of a blade portion of a pipesplitter with replaceable blades removed;

FIG. 7 is a side elevational view of the blade portion of FIG. 6;

FIG. 8 is a cross-sectional view of the blade portion of FIG. 6, thecross section taken along line 8-8 in FIG. 7;

FIG. 9 is a front elevational view of the blade portion of FIG. 6;

FIG. 10 is a side elevational view of an example of a pipe splitterincluding a blade portion with replaceable blades;

FIG. 11 is a cross-sectional view of the pipe splitter of FIG. 10, thecross section taken along line 11-11 in FIG. 10;

FIG. 12 is a front elevational view of the pipe splitter of FIG. 10;

FIG. 13 is a perspective view of an example of a blade portion of a pipesplitter with replaceable blades removed;

FIG. 14 is a side elevational view of the blade portion of FIG. 13;

FIG. 15 is a cross-sectional view of the blade portion of FIG. 13, thecross section taken along line 15-15 in FIG. 14;

FIG. 16 is a front elevational view of the blade portion of FIG. 13;

FIG. 17 is a perspective view of an example of a replaceable blade of apipe splitter;

FIG. 18 is a side elevational view of the replaceable blade of FIG. 17;

FIG. 19 is a top plan view of the replaceable blade of FIG. 17;

FIG. 20 is a front elevational view of the replaceable blade of FIG. 17;

FIG. 21 is a perspective view of an example of a blade portion of a pipesplitter with replaceable blades installed;

FIG. 22 is a side elevational view of the blade portion of FIG. 21;

FIG. 23 is a cross-sectional view of the blade portion of FIG. 21, thecross section taken along line 23-23 in FIG. 22;

FIG. 24 is a front elevational view of the blade portion of FIG. 21;

FIG. 25 is a perspective view of an example of a blade portion of a pipesplitter with replaceable blades removed;

FIG. 26 is a side elevational view of the blade portion of FIG. 25;

FIG. 27 is a cross-sectional view of the blade portion of FIG. 25, thecross section taken along line 27-27 in FIG. 26;

FIG. 28 is a front elevational view of the blade portion of FIG. 25;

FIG. 29 is a perspective view of an example of a replaceable blade of apipe splitter;

FIG. 30 is a side elevational view of the replaceable blade of FIG. 29;

FIG. 31 is a top plan view of the replaceable blade of FIG. 29;

FIG. 32 is a front elevational view of the replaceable blade of FIG. 29;

FIG. 33 is a perspective view of an example of a replaceable blade of apipe splitter;

FIG. 34 is a side elevational view of the replaceable blade of FIG. 33;

FIG. 35 is a top plan view of the replaceable blade of FIG. 33;

FIG. 36 is a front elevational view of the replaceable blade of FIG. 33;

FIG. 37 is a perspective view of an example of a replaceable blade of apipe splitter;

FIG. 38 is a side elevational view of the replaceable blade of FIG. 37;

FIG. 39 is a top plan view of the replaceable blade of FIG. 37; and

FIG. 40 is a front elevational view of the replaceable blade of FIG. 37;

DESCRIPTION OF THE EMBODIMENTS

The present inventor has recognized, among other things, that it isdesirable to provide a pipe splitting apparatus including one or morereplaceable blades to enable one to replace one or more blades after anamount of time and/or once the one or more blades have reached aparticular amount of wear. In this way, a user can replace just the oneor more blades rather than having to replace the entire pipe splittingapparatus. Replacement of one or more blades can result in less downtimeand/or less expense than the replacement of the entire pipe splittingapparatus.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized and that structuralchanges may be made without departing from the scope of the presentinvention. Therefore, the following detailed description is not to betaken in a limiting sense, and the scope of the present invention isdefined by the appended claims and their equivalents.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Also, in the following claims, theterms “including” and “comprising” are open-ended, that is, a system,device, article, or process that includes elements in addition to thoselisted after such a term in a claim are still deemed to fall within thescope of that claim. Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects.

In the following description, the term cable is defined to include metalcables, wire rope, or other lengths of flexible line of suitablestrength to pull devices as described below through a section of pipe.These embodiments are described in sufficient detail to enable thoseskilled in the art to practice the invention. Other embodiments may beutilized and structural, or logical changes, etc. may be made withoutdeparting from the scope of the present invention.

Referring to FIGS. 1-9 and 17-20, an example pipe splitting apparatus100 is shown. In the example shown, the pipe splitting apparatus 100includes a front segment 110, a pilot segment 120, and a nose segment140. In various examples, one or more of these segments 110, 120, 140can be used in various combinations and/or used with other types ofsegments. The pipe splitting apparatus 100, in an example, can becoupled to a pneumatic hammer segment, for instance, with a threadedportion 144 of the nose segment 140. The pneumatic hammer segment can beused to assist in urging the pipe splitting apparatus 100 through anexisting underground pipe or conduit to be replaced. In an example, thepneumatic hammer segment can be used in addition to pulling the pipesplitting apparatus 100 with a wire or cable extending from a cablepassage 104 of the front segment 110.

In an example, the front segment 110 is threadably engaged with a firstthreaded portion 121 of the pilot segment 120. In an example, the frontsegment 110 includes flats 112 in an outer surface to allow a tool, suchas a spanner, to be used to couple and uncouple the front segment 110and the pilot segment 120. In various examples, the nose segment 140 isthreadably engaged with a second threaded portion 123 of the pilotsegment 120. In an example, the pilot segment 120 includes flats 124 inan outer surface 122 to allow a tool, such as a spanner, to be used tocouple and uncouple the pilot segment 120 and the nose segment 140. Aswill be described in more detail below, the pilot segment 120 includesone or more blades 10 extending from the outer surface 122 of the pilotsegment 120, the one or more blades 10 being configured to bear againstand cut, score, or otherwise deform the pipe or conduit being replaced.In an example, the outer surface 122 of the pilot segment 120 iselongate. In a further example, the outer surface 122 is substantiallytubular.

In an example, the nose segment 140 includes an expander portion 142,which, in this example, substantially conically expands from a firstdiameter similar to that of the pilot segment 120 to a second largerdiameter, for instance, similar to that of the pneumatic hammer segment.The second diameter, in an example, is large enough to accommodate areplacement pipe or conduit to be advanced. The expander portion 142functions to further split and/or displace outwardly the existing pipeto allow the replacement pipe or conduit to be advanced through thespace previously occupied by the pipe or conduit being replaced. In anexample, the nose segment 140 includes one or more receptacles 146configured to accept one or more cutting blades. In an example, the oneor more blades are removably engageable within the one or morereceptacles 146. In an example, the one or more cutting blades arecarbide blades. The one or more blades are configured to assist inwidening the space previously occupied by further forcing the pipe orconduit being replaced outwardly and/or by further cutting, scoring,deforming, or scraping the pipe or conduit being replaced.

In various examples, the pilot segment 120 includes one or more recesses126 in the outer surface 122 configured to receive a correspondingnumber of blades 10 therein. In an example, the pilot segment 120includes four recesses 126 to receive four blades 10. In some examples,the pilot segment 120 includes fewer than four recesses 126 or more thanfour recesses 126. The number of recesses 126 and corresponding blades10 is dependent on various factors, including the material of the pipeor conduit being replaced, the properties of the ground through whichthe pipe or conduit being replaced is situated (such as the hardness,type of soil, amount of rocks, etc.), the material properties of the oneor more blades 10 being used, etc. In an example, the blades 10 andcorresponding recesses 126 are diametrically opposed to each otheraround the outer surface 122 of the pilot segment 120.

In various examples, the one or more recesses 126 of the pilot segment120 are each configured to accept a bottom portion 12 of the blade 10.In an example, the bottom portion 12 is sized and shaped to fit withinthe recess 126 so that a top surface of the bottom portion issubstantially flush with the outer surface 122 of the pilot segment 120and a cutting portion 14 of the blade 10 extends outwardly from theouter surface 126 of the pilot segment 120. In an example, the one ormore recesses 126 are elongate. In a further example, the one or moreelongate recesses 126 are oriented to extend substantiallylongitudinally within the outer surface 122 of the pilot segment 120. Inanother example, the one or more recesses 126 are oriented so that thecutting portion 14 of each of the blades 10 extends substantiallylongitudinally along the pilot segment 120.

In an example, the one or more blades 10 fit snugly within the one ormore recesses 126. In another example, the one or more blades 10 fitwithin the one or more recesses 126 with an amount of play between theblade 10 and the corresponding recess 126. In a further example, ahardenable material is disposed within the recess 126 and at leastpartially around the bottom portion 12 of the blade 10 disposed withinthe recess 126 to fix the blade 10 within the recess 126. The hardenablematerial, in an example, is configured to flow upon application. In anexample, the hardenable material is configured to harden afterapplication to secure the bottom portion 12 of the blade 10 within therecess 126 and fix the blade 10 to the pipe splitting apparatus 100. Inan example, the hardenable material includes an adhesive. In anotherexample, the hardenable material includes Loctite®. In still anotherexample, the hardenable material includes an epoxy. In still anotherexample, the hardenable material is solder. In this example, the solderis heated to apply the solder between the blade 10 and the recess 126.The solder acts to fix the blade 10 within the recess 126 as the soldercools and hardens. To remove the blade 10, the area of the blade 10 andrecess 126 can be heated to soften the solder in order to facilitate theremoval of the blade 10 from within the recess 126. In other examples,the hardenable material includes any substance capable of fixing orotherwise retaining the blade 10 within the recess 126.

In a further example, the blade 10 and the recess 126 are machined sothat there is a tight tolerance between substantially vertical sidewallsof the recess 126 and corresponding substantially vertical sidewalls ofthe bottom portion 12 of the blade 10. With the blade 10 inserted withinthe recess 126, during pipe splitting operations, the sidewalls of theblade 10 bear against the sidewalls of the recess 126, such that amajority of the forces are borne by the abutting sidewalls of the blade10 and the recess 126. In this way, the hardenable material actsprimarily to hold the blade 10 within the recess 126 and bears little,if any, of the forces incurred by the blade 10 during pipe splittingoperations. In an example, the bottom portion 12 of the blade 10 has aheight and/or length sufficient to provide a sufficient surface area tobear the forces incurred during pipe splitting operations.

In this way, the hardenable material acts to retain each of the blades10 within each of the recesses 126 during the useful life of each of theblades 10 or otherwise until a user decides to replace the one or moreblades 10. Also, if one or more blades 10 happen to become loose priorto the user wanting to replace them, more hardenable material can beapplied to the one or more blades 10 to again fix the one or more blades10 within the corresponding recess 126.

After an amount of time, as the one or more blades 10 have reached aparticular amount of wear, and/or if a blade of a differentconfiguration is desired, the one or more blades 10 can be replacedwithout having to replace the entire pilot segment 120. That is, each ofthe blades 10 to be replaced can be removed from the recess 126 and anew, unworn, or otherwise different blade 10 can be fixed within therecess 126 in order to continue usage of the pilot segment 120 and thepipe splitting apparatus 100. In an example, the pilot segment 120includes an elongate passage 128 extending through the outer surface 122to a portion of the recess 126 to aid in dislodging or otherwiseremoving the blade 10 fixed within the recess 126. In an example, theelongate passage 128 extends to a bottom of the recess 126, such that abottom of the bottom portion 12 of the blade 10 is accessible. In anexample, the elongate passage 128 runs from the recess 126 to the outersurface 122 of the pilot segment 120. In a further example, the openingof the elongate passage 128 is disposed in a portion of the outersurface 122 substantially opposed to the recess 126 to which theelongate passage 128 leads. In this way, an elongate tool, such as arod, can be inserted through the elongate passage 128 to contact thebottom portion 14 of the blade 10 fixed within the recess 126. Force,such as percussive force from a hammer, pneumatic or manual, or constantforce from a press, can be applied to break the bond of the hardenablematerial between the blade 10 and the recess 126 to dislodge and removethe blade 10 from within the recess 126. In an example, more than oneelongate passage 128 are included through the pilot segment 120 for eachrecess 126. In the example shown in FIGS. 1-8, two elongate passages 128are included for each recess 126. In this way, the user is able to applyforce the blade 10 at different locations along the bottom portion 12 tourge the blade 10 out of the recess 126. Once the blade 10 to bereplaced is removed, another blade 10 can be fixed within the recess 126using hardenable material.

In other examples, replaceable blades 10 can be used with segments otherthan or in addition to the pilot segment 120 described above. Forinstance, with reference to FIGS. 10-16, a pipe splitting apparatus 200is shown having a pilot segment 220 with replaceable blades 10. The pipesplitting apparatus 200 includes the pilot segment 220, a segmentcartridge 230, and a nose segment 240. In this example, the pilotsegment 220 is disposed at the front of the pipe splitting apparatus 200and includes a cable passage 204 at a front end of the pilot segment 220from which a wire or cable extends during a pulling operation. Thesegment cartridge 230 is coupled at a proximal end of the pilot segment220. A proximal portion of the segment cartridge 230 is threadablyengaged to the nose segment 240. In an example, the segment cartridge230 includes flats 232 in an outer surface to allow a tool, such as aspanner, to be used to couple and uncouple the segment cartridge 230 andthe nose segment 240. In various examples, one or more of these segments220, 230, 240 can be used in various combinations and/or used with othertypes of segments. The pipe splitting apparatus 200, in an example, canbe coupled to a pneumatic hammer segment, for instance, with a threadedportion 244 of the nose segment 240. The pneumatic hammer segment can beused to assist in urging the pipe splitting apparatus 200 through anexisting underground pipe or conduit to be replaced. In an example, thepneumatic hammer segment can be used in addition to pulling the pipesplitting apparatus 200 with the wire or cable extending from the cablepassage 204 of the pilot segment 220.

In an example, the nose segment 240 includes an expander portion 242,which, in this example, substantially conically expands from a firstdiameter similar to that of the segment cartridge 230 to a second largerdiameter, for instance, similar to that of the pneumatic hammer segment.The second diameter, in an example, is large enough to accommodate areplacement pipe or conduit to be advanced. The expander portion 242functions to further split and/or displace outwardly the existing pipeto allow the replacement pipe or conduit to be advanced through thespace previously occupied by the pipe or conduit being replaced. In anexample, the nose segment 240 includes one or more receptacles 246configured to accept one or more cutting blades. In an example, the oneor more blades are removably engageable within the one or morereceptacles 246. In an example, the one or more cutting blades arecarbide blades. The one or more blades are configured to assist inwidening the space previously occupied by further forcing the pipe orconduit being replaced outwardly and/or by further cutting, scoring,deforming, or scraping the pipe or conduit being replaced.

In various examples, the pilot segment 220 includes one or more recesses226 in an outer surface 222 configured to receive a corresponding numberof blades 10 therein. In an example, the pilot segment 220 includes fourrecesses 226 to receive four blades 10. In some examples, the pilotsegment 220 includes fewer than four recesses 226 or more than fourrecesses 226. The number of recesses 226 and corresponding blades 10 aredependent on various factors, including the material of the pipe orconduit being replaced, the properties of the ground through which thepipe or conduit being replaced is situated (such as the hardness, typeof soil, amount of rocks, etc.), the material properties of the one ormore blades 10 being used, etc. In an example, the blades 10 andcorresponding recesses 226 are diametrically opposed to each otheraround the outer surface 222 of the pilot segment 220.

In various examples, the one or more recesses 226 of the pilot segment220 are each configured to accept the bottom portion 12 of the blade 10.In an example, the bottom portion 12 is sized and shaped to fit withinthe recess 226 so that a top surface of the bottom portion issubstantially flush with the outer surface 222 of the pilot segment 220and the cutting portion 14 of the blade 10 extends outwardly from theouter surface 226 of the pilot segment 220. In an example, the one ormore recesses 226 are elongate. In a further example, the one or moreelongate recesses 226 are oriented to extend substantiallylongitudinally within the outer surface 222 of the pilot segment 220. Inanother example, the one or more recesses 226 are oriented so that thecutting portion 14 of each of the blades 10 extends substantiallylongitudinally along the pilot segment 220.

In an example, the one or more blades 10 fit snugly within the one ormore recesses 226. In another example, the one or more blades 10 fitwithin the one or more recesses 226 with an amount of play between theblade 10 and the corresponding recess 226. In a further example, ahardenable material is disposed within the recess 226 and at leastpartially around the bottom portion 12 of the blade 10 disposed withinthe recess 226 to fix the blade 10 within the recess 226. The hardenablematerial, in an example, is configured to flow upon application. In anexample, the hardenable material is configured to harden afterapplication to secure the bottom portion 12 of the blade 10 within therecess 226 and fix the blade 10 to the pipe splitting apparatus 200. Inan example, the hardenable material includes an adhesive. In anotherexample, the hardenable material includes Loctite®. In still anotherexample, the hardenable material includes an epoxy. In still anotherexample, the hardenable material is solder. In this example, the solderis heated to apply the solder between the blade 10 and the recess 226.The solder acts to fix the blade 10 within the recess 226 as the soldercools and hardens. To remove the blade 10, the area of the blade 10 andrecess 226 can be heated to soften the solder in order to facilitate theremoval of the blade 10 from within the recess 226. In other examples,the hardenable material includes any substance capable of fixing orotherwise retaining the blade 10 within the recess 226.

In a further example, the blade 10 and the recess 226 are machined sothat there is a tight tolerance between substantially vertical sidewallsof the recess 226 and corresponding substantially vertical sidewalls ofthe bottom portion 12 of the blade 10. With the blade 10 inserted withinthe recess 226, during pipe splitting operations, the sidewalls of theblade 10 bear against the sidewalls of the recess 226, such that amajority of the forces are borne by the abutting sidewalls of the blade10 and the recess 226. In this way, the hardenable material actsprimarily to hold the blade 10 within the recess 226 and bears little,if any, of the forces incurred by the blade 10 during pipe splittingoperations. In an example, the bottom portion 12 of the blade 10 has aheight and/or length sufficient to provide a sufficient surface area tobear the forces incurred during pipe splitting operations.

In this way, the hardenable material acts to retain each of the blades10 within each of the recesses 226 during the useful life of each of theblades 10 or otherwise until a user decides to replace the one or moreblades 10. Also, if one or more blades 10 happen to become loose priorto the user wanting to replace them, more hardenable material can beapplied to the one or more blades 10 to again fix the one or more blades10 within the corresponding recess 226.

After an amount of time, as the one or more blades 10 have reached aparticular amount of wear, and/or if a blade of a differentconfiguration is desired, the one or more blades 10 can be replacedwithout having to replace the entire pilot segment 220. That is, each ofthe blades 10 to be replaced can be removed from the recess 226 and anew, unworn, or otherwise different blade 10 can be fixed within therecess 226 in order to continue usage of the pilot segment 220 and thepipe splitting apparatus 200. In an example, the pilot segment 220includes an elongate passage 228 extending through the outer surface 222to a portion of the recess 226 to aid in dislodging or otherwiseremoving the blade 10 fixed within the recess 226. In an example, theelongate passage 228 extends to a bottom of the recess 226, such that abottom of the bottom portion 12 of the blade 10 is accessible. In anexample, the elongate passage 228 runs from the recess 226 to the outersurface 222 of the pilot segment 220. In a further example, the openingof the elongate passage 228 is disposed in a portion of the outersurface 222 substantially opposed to the recess 226 to which theelongate passage 228 leads. In this way, an elongate tool, such as arod, can be inserted through the elongate passage 228 to contact thebottom portion 14 of the blade 10 fixed within the recess 226. Force,such as percussive force from a hammer, pneumatic or manual, or constantforce from a press, can be applied to break the bond of the hardenablematerial between the blade 10 and the recess 226 to dislodge and removethe blade 10 from within the recess 226. In an example, more than oneelongate passage 228 are included through the pilot segment 220 for eachrecess 226. In the example shown in FIGS. 10-16, two elongate passages228 are included for each recess 226. In this way, the user is able toapply force the blade 10 at different locations along the bottom portion12 to urge the blade 10 out of the recess 226. Once the blade 10 to bereplaced is removed, another blade 10 can be fixed within the recess 226using hardenable material.

With reference to FIGS. 21-29, in an example, a scoring pilot segment320 includes replaceable scoring blades 20 and is substantially similarto the example pilot segments 120, 220 described above. The scoringpilot segment 320 can be used instead of or in addition to the pilotsegments 120, 220 of the pipe splitting apparatuses 100, 200 describedabove or can be used in another apparatus different from the pipesplitting apparatuses 100, 200. In an example, the scoring pilot segment320 includes a cable passage 304 at a front end from which a cable orwire extends during a pulling operation. In an example, the scoringpilot segment 320 includes a outer surface 322. In a further example,the outer surface 322 is elongate. In a further example, the outersurface 322 is substantially tubular.

In various examples, the scoring pilot segment 320 includes one or morerecesses 326 in the outer surface 322 configured to receive acorresponding number of blades 20 therein. In an example, the scoringpilot segment 320 includes two bands of recesses 326 having fourrecesses 326 in each band. In some examples, the scoring pilot segment320 includes fewer than four recesses 326 or more than four recesses 326in a band or includes more or less than two bands of recesses 326. Thenumber of recesses 326 and bands of recesses 326 and correspondingblades 20 are dependent on various factors, including the material ofthe pipe or conduit being replaced, the properties of the ground throughwhich the pipe or conduit being replaced is situated (such as thehardness, type of soil, amount of rocks, etc.), the material propertiesof the one or more blades 20 being used, etc. In an example, the blades20 and corresponding recesses 326 are diametrically opposed to eachother around the outer surface 322 of the scoring pilot segment 320.

In various examples, the one or more recesses 326 of the scoring pilotsegment 320 are each configured to accept the bottom portion 22 of theblade 20. In an example, the bottom portion 22 is sized and shaped tofit within the recess 326 so that a top surface of the bottom portion issubstantially flush with the outer surface 322 of the scoring pilotsegment 320 and a cutting portion 24 of the blade 20 extends outwardlyfrom the outer surface 326 of the scoring pilot segment 320. In anexample, the one or more recesses 326 are elongate. In a furtherexample, the one or more elongate recesses 326 are oriented to extendsubstantially longitudinally within the outer surface 322 of the scoringpilot segment 320. In another example, the one or more recesses 326 areoriented so that the cutting portion 24 of each of the blades 20 extendssubstantially longitudinally along the scoring pilot segment 320.

In an example, the one or more blades 20 fit snugly within the one ormore recesses 326. In another example, the one or more blades 20 fitwithin the one or more recesses 326 with an amount of play between theblade 20 and the corresponding recess 326. In a further example, ahardenable material is disposed within the recess 326 and at leastpartially around the bottom portion 22 of the blade 20 disposed withinthe recess 326 to fix the blade 20 within the recess 326. The hardenablematerial, in an example, is configured to flow upon application. In anexample, the hardenable material is configured to harden afterapplication to secure the bottom portion 22 of the blade 20 within therecess 326 and fix the blade 20 to the pipe splitting apparatus 300. Inan example, the hardenable material includes an adhesive. In anotherexample, the hardenable material includes Loctite®. In still anotherexample, the hardenable material includes an epoxy. In still anotherexample, the hardenable material is solder. In this example, the solderis heated to apply the solder between the blade 20 and the recess 326.The solder acts to fix the blade 20 within the recess 326 as the soldercools and hardens. To remove the blade 20, the area of the blade 20 andrecess 326 can be heated to soften the solder in order to facilitate theremoval of the blade 20 from within the recess 326. In other examples,the hardenable material includes any substance capable of fixing orotherwise retaining the blade 20 within the recess 326.

In a further example, the blade 20 and the recess 326 are machined sothat there is a tight tolerance between substantially vertical sidewallsof the recess 326 and corresponding substantially vertical sidewalls ofthe bottom portion 22 of the blade 20. With the blade 20 inserted withinthe recess 326, during pipe splitting operations, the sidewalls of theblade 20 bear against the sidewalls of the recess 326, such that amajority of the forces are borne by the abutting sidewalls of the blade20 and the recess 326. In this way, the hardenable material actsprimarily to hold the blade 20 within the recess 326 and bears little,if any, of the forces incurred by the blade 20 during pipe splittingoperations. In an example, the bottom portion 22 of the blade 20 has aheight and/or length sufficient to provide a sufficient surface area tobear the forces incurred during pipe splitting operations.

In this way, the hardenable material acts to retain each of the blades20 within each of the recesses 326 during the useful life of each of theblades 20 or otherwise until a user decides to replace the one or moreblades 20. Also, if one or more blades 20 happen to become loose priorto the user wanting to replace them, more hardenable material can beapplied to the one or more blades 20 to again fix the one or more blades20 within the corresponding recess 326.

After an amount of time, as the one or more blades 20 have reached aparticular amount of wear, and/or if a blade of a differentconfiguration is desired, the one or more blades 20 can be replacedwithout having to replace the entire scoring pilot segment 320. That is,each of the blades 20 to be replaced can be removed from the recess 326and a new, unworn, or otherwise different blade 20 can be fixed withinthe recess 326 in order to continue usage of the scoring pilot segment320. In an example, the scoring pilot segment 320 includes an elongatepassage 328 extending through the outer surface 322 to a portion of therecess 326 to aid in dislodging or otherwise removing the blade 20 fixedwithin the recess 326. In an example, the elongate passage 328 extendsto a bottom of the recess 326, such that a bottom of the bottom portion22 of the blade 20 is accessible. In an example, the elongate passage328 runs from the recess 326 to the outer surface 322 of the scoringpilot segment 320. In a further example, the opening of the elongatepassage 328 is disposed in a portion of the outer surface 322substantially opposed to the recess 326 to which the elongate passage328 leads. In this way, an elongate tool, such as a rod, can be insertedthrough the elongate passage 328 to contact the bottom portion 24 of theblade 20 fixed within the recess 326. Force, such as percussive forcefrom a hammer, pneumatic or manual, or constant force from a press, canbe applied to break the bond of the hardenable material between theblade 20 and the recess 326 to dislodge and remove the blade 20 fromwithin the recess 326. In an example, more than one elongate passage 328are included through the scoring pilot segment 320 for each recess 326.In the example shown in FIGS. 21-28, two elongate passages 328 areincluded for each recess 326. In this way, the user is able to applyforce the blade 20 at different locations along the bottom portion 22 tourge the blade 20 out of the recess 326. Once the blade 20 to bereplaced is removed, another blade 20 can be fixed within the recess 326using hardenable material.

Referring to FIGS. 19-20 and 31-40, variously configured blades 10, 20,30, 40 are depicted. In some examples, the blades 10, 20, 30, 40primarily vary from each other in the configurations of cutting portions14, 24, 34, 44 of the blades 10, 20, 30, 40. In some examples, bottomportions 12, 22, 32, 42 of the blades 10, 20, 30, 40 are substantiallysimilar to allow the bottom portions 12, 22, 32, 42 to fit within therecesses 126, 226, 326 of the pilot segments 120, 220, 320, as describedabove. The configurations of the cutting portions 14, 24, 34, 44 vary inseveral ways according to the task to be accomplished with the blade 10,20, 30, 40 (for instance, splitting, scoring, etc.), the materialproperties of the pipe or conduit to be split, the properties of theground surrounding the pipe or conduit to be split, etc. For instance,the blades 10, 20, 30, 40 shown differ from one another in height of thecutting portion 14, 24, 34, 44, width of the cutting portion 14, 24, 34,44, and/or angle of a leading edge of the cutting portion 14, 24, 34,44. It should be understood that configurations, other than the fourconfigurations of blades 10, 20, 30, 40 shown and described herein, arecontemplated herein, with varying widths, heights, and leading edgeangles.

Although only the blades 10, 20 are described above as being replaceablyengaged with the pilot segments 120, 220, 320, any of the blades 10, 20,30, 40 shown and described herein, as well as any other configurationsof blades not shown herein, are capable of being fixed within therecesses 126, 226, 326 of the pilot segments 120, 220, 320. That is,although the blade 10 is shown and described with respect to the pilotsegments 120, 220, it is contemplated that the blades 20, 30, 40 be usedwith the pilot segments 120, 220, either instead of or in combinationwith the blade 10 or in combination with each other. Likewise, althoughthe blade 20 is shown and described with respect to the scoring pilotsegment 320, it is contemplated that the blades 10, 30, 40 be used withthe scoring pilot segment 320, either instead of or in combination withthe blade 20 or in combination with each other. That is, the pilotsegment 120, 220, 320 can include all of the same configuration of blade10, 20, 30, 40 or a combination of two or more configurations of blades10, 20, 30, 40, depending upon the application for which the pilotsegment 120, 220, 320 is being used.

In an example, with reference to FIGS. 1-40 and the above description, amethod of use of replaceable blades 10, 20, 30, 40 includes inserting abottom portion 12, 22, 32, 42 of the blade 10, 20, 30, 40 within arecess 126, 226, 326 of a pilot segment 120, 220, 320 of, for instance,a pipe splitting apparatus 100, 200. A hardenable material is appliedwithin the recess 126, 226, 326 and at least partially around the bottomportion 12, 22, 32, 42 of the blade 10, 20, 30, 40. The hardenablematerial hardens after application to secure the bottom portion 12, 22,32, 42 of the blade 10, 20, 30, 40 within the recess 126, 226, 326 andfix the blade 10, 20, 30, 40 to the pilot segment 120, 220, 320.

In an example, the hardenable material is removed from within the recess126, 226, 326 to allow for a worn or otherwise undesirable blade 10, 20,30, 40 to be removed from within the recess 126, 226, 326. A portion ofa different blade 10, 20, 30, 40 can be inserted within the recess 126,226, 326. The hardenable material is applied within the recess 126, 226,326 and at least partially around the bottom portion 12, 22, 32, 42 ofthe different blade 10, 20, 30, 40. The hardenable material hardensafter application to secure the bottom portion 12, 22, 32, 42 of thedifferent blade 10, 20, 30, 40 within the recess and fix the differentblade 10, 20, 30, 40 to the pilot segment 120, 220, 320. In this way,the undesirable blade 10, 20, 30, 40 can be replaced without having toreplace the entire pilot segment 120, 220, 320. In an example, a bottomportion 12, 22, 32, 42 of an unused blade 10, 20, 30, 40 is insertedwithin the recess 126, 226, 326. Various reasons for replacing blades10, 20, 30, 40 are contemplated. For instance, it may be desirable toreplace a worn blade 10, 20, 30, 40 which has become ineffective due tothe amount of wear or to replace a blade 10, 20, 30, 40 of a particularconfiguration with a blade 10, 20, 30, 40 of a different configuration.

In an example, an elongate member, such as a rod, is inserted within anelongate passage 128, 228, 328 through the pilot segment 120, 220, 320to push the blade 10, 20, 30, 40 to be replaced out of the recess 126,226, 326. In a further example, at least some of the hardened hardenablematerial is removed from within the recess 126, 226, 326 after removalof the blade 10, 20, 30, 40 to be replaced and before insertion of theother blade 10, 20, 30, 40 replacing the previous blade 10, 20, 30, 40.

As described with respect to the examples above, the replaceable blades10, 20, 30, 40 of the pilot segment 120, 220, 320 allow for one or moreblades 10, 20, 30, 40 of the pilot segment 120, 220, 320 to be replacedwithout having to replace the entire pilot segment 120, 220, 320. One ormore blades 10, 20, 30, 40 can be replaced, for instance, if the one ormore blades 10, 20, 30, 40 become worn, if a particular amount of usagetime for the one or more blades 10, 20, 30, 40 has been reached, if adifferent configuration of blade 10, 20, 30, 40 is desired, etc. In thisway, the replaceable blades 10, 20, 30, 40 are advantageous in thatreplacement of one or more blades 10, 20, 30, 40 can result in lessdowntime and/or less expense than the replacement of the entire pilotsegment 120, 220, 320.

CONCLUSION

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments may be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. A pipe splitting apparatus comprising: an outersurface including a recess; a blade including a portion disposed andsecured within the recess; an elongate passage extending through theouter surface to a portion of the recess, the passage configured toallow access to the blade, when disposed within the recess, to push theblade out of the recess.
 2. The pipe splitting apparatus of claim 1,comprising a hardenable material disposed within the recess and at leastpartially around the portion of the blade disposed within the recess,the hardenable material configured to flow upon application, wherein thehardenable material is configured to harden after application to securethe portion of the blade within the recess and fix the blade to the pipesplitting apparatus.
 3. The pipe splitting apparatus of claim 2, whereinthe hardenable material includes an adhesive.
 4. The pipe splittingapparatus of claim 2, wherein the hardenable material includes an epoxy.5. The pipe splitting apparatus of claim 2, wherein the hardenablematerial includes solder.
 6. The pipe splitting apparatus of claim 1,wherein the recess includes at least one rounded end.
 7. The pipesplitting apparatus of claim 1, wherein the outer surface includes morethan one recess, each recess being configured to receive a blade.
 8. Thepipe splitting apparatus of claim 7, wherein the pipe splittingapparatus includes at least two opposed blades.
 9. The pipe splittingapparatus of claim 7, wherein the pipe splitting apparatus includes fourblades.
 10. The pipe splitting apparatus of claim 7, wherein the pipesplitting apparatus includes more than four blades.
 11. The pipesplitting apparatus of claim 10, wherein the pipe splitting apparatusincludes a first set of four blades and a second set of four blades. 12.The pipe splitting apparatus of claim 11, wherein the second set of fourblades is offset from the first set of four blades.
 13. The pipesplitting apparatus of claim 12, wherein the second set of four bladesis offset by substantially forty-five degrees from the first set of fourblades.
 14. The pipe splitting apparatus of claim 11, wherein the secondset of four blades is disposed at least partially behind the first setof four blades.
 15. A method comprising: removing a first worn bladefrom within a recess, wherein removing the first worn blade includesinserting an elongate member within a passage through a pipe splitter topush the first worn blade out of the recess; inserting a portion of asecond blade within a recess of the pipe splitter; securing the portionof the second blade within the recess to fix the second blade to thepipe splitting apparatus.
 16. The method of claim 15, wherein securingthe portion of the second blade includes applying a hardenable materialwithin the recess and at least partially around the portion of theblade, wherein the hardenable material hardens after application tosecure the portion of the blade within the recess and fix the blade tothe pipe splitting apparatus.
 17. The method of claim 16, whereinremoving the first worn blade includes removing at least some of thehardened hardenable material from within the recess.
 18. The method ofclaim 16, wherein applying the hardenable material includes applying anadhesive.
 19. The method of claim 16, wherein applying the hardenablematerial includes applying an epoxy.
 20. The method of claim 16, whereinapplying the hardenable material includes applying solder.
 21. Themethod of claim 20, wherein removing the first worn blade includesheating the first worn blade or the recess to soften the solder tofacilitate removal of the first worn blade.
 22. The method of claim 15,wherein inserting the portion of the second blade includes inserting aportion of an unused blade.
 23. An apparatus comprising: a pipesplitter, comprising: a tubular, elongate outer surface including anelongate recess; a blade including a portion disposed and secured withinthe recess; and a passage extending through the outer surface to aportion of the recess, the passage configured to allow access to theblade, when disposed within the recess, to push the blade out of therecess; a pneumatic hammer segment operatively coupled to the pipesplitter, the pneumatic hammer segment configured to facilitate pipesplitting with the apparatus.
 24. The apparatus of claim 23, comprisinga hardenable material disposed within the recess and at least partiallyaround the portion of the blade disposed within the recess, thehardenable material configured to flow upon application, wherein thehardenable material is configured to harden after application to securethe portion of the blade within the recess and fix the blade to the pipesplitting apparatus.
 25. A pipe splitting system comprising: a pilotsegment including an outer surface substantially matching an innerdiameter of a pipe to be replaced, the outer surface of the pilotsegment including a recess; a front segment coupled in front of thepilot segment; an expander coupled behind the pilot segment; a bladeincluding a portion disposed and secured within the recess; and apassage extending through the outer surface to a portion of the recess,the passage configured to allow access to the blade, when disposedwithin the recess, to push the blade out of the recess.
 26. The pipesplitting system of claim 25, wherein the pilot segment is threadablycoupled to the front segment.
 27. The pipe splitting system of claim 25,wherein at least one of the pilot segment and the front segment includewrench flats.
 28. The pipe splitting system of claim 25, wherein thepassage extends from the outer surface to the portion of the recess atan angle from a line perpendicular to a longitudinal axis of the pilotsegment.
 29. The pipe splitting system of claim 25, comprising fourblades disposed substantially evenly around the pilot segment atsubstantially ninety degree increments.
 30. The pipe splitting system ofclaim 25, comprising: a first set of four blades disposed substantiallyevenly around the pilot segment at substantially ninety degreeincrements; and a second set of four blades disposed substantiallyevenly around the pilot segment at substantially ninety degreeincrements, wherein the second set of four blades is offset from thefirst set of four blades by substantially forty-five degrees.